Conventional track assemblies utilized on track-type machines have typically consisted of a pair of parallel track chains comprised of a plurality of link members that are interconnected by laterally disposed track pins. A track bushing is commonly disposed about the pin and is secured to the links. The bushing is adapted to engage a drive sprocket that propels the track assembly about a track roller frame and ultimately provides the tractive force necessary to power the machine. In recent times and for certain applications, the bushing has taken the form of a "roller" bushing and is not fixed to the links but rather is allowed to rotate about the pin relative to both the pin and the links. This design reduces the wear between the drive sprocket and the bushings which has been known to be quite severe, especially in the abrasive conditions in which track-type machines commonly operate.
Another source of wear occurs on the link members of the track chain. The link members commonly have a wear rail defined on an inwardly directed surface that engages the wear surfaces on the guide rollers and the idlers mounted to the track roller frame. As the track assembly rotates about the track frame, the wear rails of the links are continually brought into contact with the wear surfaces and are thus subjected to severe wear. This is especially critical at the interface between the idlers and the wear rails of the links. Conventional idlers are relatively large diameter wheels that have a pair of laterally extending wear surfaces, or treads, which are positioned to contact the wear rails of the links. An idler is further identified as a non-driving wheel that is positioned between the treads and which runs between the links to act as lateral guides for the track chains at one or more ends of a track assembly. The track assembly may have a single idler in the case of a generally oval track or there may be a pair of idlers in the case of a triangular track configuration. As the generally planar surface of the wear rails is continually brought into contact with the circular idler wheel or wheels of conventional idlers, an arcuate surface begins to form on the wear rails. This wear, of course, is accelerated in more abrasive soils. When this type of wear occurs, the arcuate wear surface will create a highly uneven "platform" or "scallop" for the machine as the track chain lays on the ground and the guide rollers roll across the guide rails. This results in an extremely rough ride due to vibration which is not only uncomfortable for the operator of the machine, it is also structurally fatiguing to tractor components. Additionally, the noise of the metal on metal contact of the idlers striking the guide rails is often unpleasant and fatiguing to the machine operator.
The present invention is directed to overcoming one or more of the problems set forth above.